The present invention broadly relates to weaving machines and, more specifically, pertains to a new and improved construction of a warp let-off control device for weaving machines, especially for weaving machines with two or more partial or segmental warp beams.
Generally speaking, the warp let-off control device of the present invention comprises a warp beam, a stationary bar-shaped deflection element for the warp arranged subsequent to the warp beam in the direction of motion of the warp or warp threads as well as a tensioning beam movable by spring action and arranged subsequent to the deflection element in the direction of motion of the warp.
In a previously known control device of this type (cf. Swiss Pat. No. 629,549, granted Apr. 30, 1982) the warp let-off speed is controlled in that the tension, respectively the position, of the warp is sensed by the movable tensioning beam itself. According to the position of the tensioning beam, a signal is transmitted to the control device through an associated sensor. The control device transmits an appropriate signal to the warp beam drive means, whereby the warp let-off speed is adjusted. The reaction speed of this known warp let-off control device is limited in that the entire tensioning beam must follow warp tension changes, for which a certain time interval is required; consequently the warp let-off speed can only be adjusted after this time interval has passed.